Illumination devices and methods of fabrication thereof

• US 9,121,979 B2
• Filed: 05/27/2010
• Issued: 09/01/2015
• Est. Priority Date: 05/29/2009
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Bita, Ion, Patel, Sapna, Chan, Clayton Ka Tsun, Ganti, SuryaPrakash, Arbuckle, Brian W.
• Primary Examiner(s): Allen, Stephone B
• Assistant Examiner(s): THOMAS, BRANDI N
• Application Number:
  US12/789,415
• Publication Number:
  US 20100302616A1
• Time in Patent Office: 1,923 Days
• Field of Search: 359290-292, 359/295, 359/298, 359/242, 359/267, 359/277, 359/282, 362/559, 362/561, 367/68, 369/25, 369/30
• US Class Current: 1/1
• CPC Class Codes: G02B 26/001 based on interference in an adjustable optical cavity interference filters G02B5/28; devices or arrangements using multiple reflections in spectrometry or monochromators G01J3/26
• CPC Class Codes: G02B 6/0036 2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• CPC Class Codes: G02B 6/0065 Manufacturing aspects; Material aspects
• CPC Class Codes: G02F 1/133616 Front illuminating devices

Abstract

Illumination devices and methods of making same are disclosed. In one embodiment, a display device includes a light modulating array and a light guide configured to receive light into at least one edge of the light guide. The light guide can be characterized by a first refractive index. The display device can also include a light turning layer disposed such that the light guide is at least partially between the turning layer and the array. The turning layer can comprise an inorganic material characterized by a second refractive index that is substantially the same as the first refractive index.

Claims

1. A display device comprising:

an array of light modulating elements;

a light guide disposed over the array, the light guide having at least one edge configured to receive light into the light guide, the light guide including a first inorganic material characterized by a first refractive index; and

a turning layer disposed such that the light guide is at least partially between the turning layer and the array, the turning layer including a second inorganic material characterized by a second refractive index that is substantially the same as the first refractive index, wherein the first inorganic material is different than the second inorganic material.

2. The device of claim 1, wherein the light guide comprises an aluminosilicate.

3. The device of claim 1, wherein the light guide comprises sapphire.

4. The device of claim 1, wherein the turning layer comprises silicon oxynitride (SiO_xN).

5. The device of claim 4, wherein the light guide comprises sapphire or an aluminosilicate.

6. The device of claim 1, wherein the first refractive index is between about 1.45 and 2.06.

7. The device of claim 1, further comprising a light source configured to provide light into the edge of the light guide.

8. The device of claim 1, further comprising an isolation layer disposed at least partially between the light guide and the array, the isolation layer characterized by a third refractive index that is substantially less than the first refractive index.

9. The device of claim 1, wherein the turning layer further comprises a plurality of light turning features, each light turning feature being configured to receive at least a portion of light which is propagating through the turning layer and reflect at least a portion of the received light toward the array.

10. The device of claim 9, wherein each light turning feature comprises a depression formed in a surface of the turning layer.

11. The device of claim 9, wherein each light turning feature has a generally frustoconical shape.

12. The device of claim 9, wherein each light turning feature has a tapered sidewall.

13. The device of claim 12, wherein each turning feature comprises an interferometric modulator disposed on the tapered sidewall.

14. The device of claim 13, wherein the interferometric modulator comprises a first reflective layer, a second layer, and a third partially reflective layer disposed respectively on the tapered sidewall, wherein the first layer is configured to receive light propagating within the turning layer and reflect at least a portion of the received light toward the array.

15. The device of claim 14, wherein the first, second, and third layers are configured to block a portion of light incident on the turning layer from reflecting from the light guide.

16. The device of claim 1, wherein the light guide further comprises a plurality of light turning features, each light turning feature comprising a tapered sidewall and an optical stack formed thereon.

17. The device of claim 1, further comprising:

a processor that is configured to communicate with the array of light modulating elements, said processor being configured to process image data; and

a memory device that is configured to communicate with said processor.

18. The device of claim 17, further comprising a driver circuit configured to send at least one signal to the array of light modulating elements.

19. The device of claim 18, further comprising a controller configured to send at least a portion of the image data to said driver circuit.

20. The device of claim 17, further comprising an image source module configured to send the image data to the processor.

21. The device of claim 20, wherein said image source module comprises at least one of a receiver, transceiver, and transmitter.

22. The device of claim 17, further comprising an input device configured to receive input data and to communicate said input data to said processor.

23. A display device comprising:

a light modulating device; and

a light guide disposed over the light modulating device, the light guide being configured to receive light into at least one edge of the light guide, the light guide including

a light-transmissive inorganic substrate layer including a first material characterized by a first refractive index, and

a inorganic turning layer disposed over the light-transmissive inorganic substrate layer, the inorganic turning layer including a second material characterized by a second refractive index that is substantially the same as the first refractive index, the inorganic turning layer including a plurality of light turning features configured to receive at least a portion of light propagating within the light guide and reflect at least a portion of the received light toward the light modulating device, wherein the first material is different than the second material.

24. The display device of claim 23, further comprising a plurality of optical masks formed on the light turning features.

25. The display device of claim 24, wherein the optical masks comprise dark coatings.

26. The display device of claim 24, wherein the optical masks comprise interferometric stacks.

27. A display device, comprising:

means for modulating light;

means for guiding light disposed over the modulating means, the guiding means including a first inorganic material characterized by a first refractive index; and

means for turning light disposed such that the guiding means is at least partially between the modulating means and the turning means, the turning means including a second inorganic material characterized by a second refractive index that is substantially the same as the first refractive index, wherein the first inorganic material is different than the second inorganic material.